RE: [Sipping] Use cases of multi-transcoding

["Michael Hammer \(mhammer\)" <[e-mail]>]

Henry,

Free != IPR-free

Mike
 

> -----Original Message-----
> From: Henry Sinnreich [mailto:[e-mail]] 
> Sent: Wednesday, March 08, 2006 8:32 AM
> To: [e-mail]; 'Roy, Radhika R.'; [e-mail]
> Subject: RE: [Sipping] Use cases of multi-transcoding
> 
> Brian,
> 
> >I don't think vendor's opinion has changed, and I don't 
> think you can 
> >mandate any standard except G.711.
> 
> In pessimistic mood today? :-)>
> 
> Not only has Skype shown that VoIP quality can go over the 
> deplorable 5.0 MOS scale, but that also echo control, side 
> tone control, automatic level control, noise cancellation, 
> wideband audio, etc. can be deployed in a free download 150 
> million times! (5,467,770 users right now on line).
> 
> Opinions of many decision makers has changed as a consequence.
> 
> G.7xx codecs should however be paid due reverence is history books.
> 
> Roy is right:
> 
> >It is the time to select “DEFAULT” codec by the IETF for the 
> Internet. >SIPPING/SIP WG needs to mandate this.
> 
> Thanks, Henry 
> 
> 
> -----Original Message-----
> From: Brian Rosen [mailto:[e-mail]]
> Sent: Wednesday, March 08, 2006 7:05 AM
> To: 'Roy, Radhika R.'; [e-mail]
> Subject: RE: [Sipping] Use cases of multi-transcoding
> 
> You know, I've always thought the default codec for VoIP 
> should be a wideband codec, with G.711 provided for backwards 
> compatibility only.  If VoIP always implied 
> better-than-"toll-quality", it would mean something different 
> than it does now.  We showed this in user trials.  Skype 
> showed how true this is in the wild. 
> 
> Vendors never agreed; they were all looking to duplicate 
> black phones.  Customers don't know enough to ask; it only 
> rarely shows up on wish lists and almost never on 
> requirements documents.  They don't know what they are 
> missing and how little it costs to substantially improve user 
> experience.
> 
> We found really odd problems trying to do it.  The one that 
> really hurt was if you want a handset that was wideband AND 
> met disability requirements for hearing aid compatibility, 
> there were no choices; you had to literally build your own 
> handset, with hard-to-find components.
> 
> I don't think vendor's opinion has changed, and I don't think 
> you can mandate any standard except G.711.  I don't think 
> I've seen a wired SIP phone that didn't do G.711.  Not really 
> sure if there has been a wireless one offered.  
> 
> Brian
> 
> 
> 
> ________________________________________
> From: Roy, Radhika R. [mailto:[e-mail]]
> Sent: Tuesday, March 07, 2006 2:08 PM
> To: [e-mail]
> Subject: RE: [Sipping] Use cases of multi-transcoding
> 
> Hi, Kang, Henry, and all:
> 
> It is the time to select “DEFAULT” codec by the IETF for the 
> Internet. SIPPING/SIP WG needs to mandate this. 
> 
> (In olden days, ITU-T defined their default G.711 audio codec 
> for the IP Network mandating PSTN network interoperability 
> [ridiculous!!]. Then IMTC did something mandating a 
> lower-speed codec.)
> 
> Some proposals are coming from your side. Can we get the 
> consensus to mandate these requirements for the Internet to 
> the benefit of the users?
> 
> Best regards,
> Radhika
> 
> ________________________________________
> From: [e-mail] 
> [mailto:[e-mail]] On Behalf Of Henry Sinnreich
> Sent: Tuesday, March 07, 2006 9:24 AM
> To: Kang Tae-Gyu; [e-mail]
> Cc: [e-mail]
> Subject: RE: [Sipping] Use cases of multi-transcoding
> 
> Kang,
> 
> It seems there are several issues in this debate (in 
> increasing order of disruption ☺ ):
> 
> 1. Are there too many codecs around? If yes, what is the 
> minimum number of codecs that should be supported? What is 
> the recommended default codec? (As mentioned, my pick is iLBC 
> as the default and SPEEX for wideband).
> 
> 2. Can transcoding between domains be avoided or at least 
> minimized? (Hint: Avoided at all cost).
> 
> 3. Why are intermediate VoIP domains necessary at all, when 
> e2e services like Skype have proven to be successful and 
> having the best audio quality (apart from the e2e QoS 
> debate)? Editorial: Intermediate VoIP domains are IMHO a 
> revenue objective, but have no technical justification on the 
> e2e Internet and no amount of politics can prevail in the 
> long term over sound technology.
> Thanks, Henry
> ________________________________________
> From: Kang Tae-Gyu [mailto:[e-mail]]
> Sent: Tuesday, March 07, 2006 1:30 AM
> To: Henry Sinnreich; [e-mail]
> Cc: [e-mail]
> Subject: RE: [Sipping] Use cases of multi-transcoding
> 
> Hi, Henry
> If industry has a specific "internet codec", SIP/SDP will be 
> more simple signaling protocol.
> But, I believe that SIP/SDP tries to support any codec and any media.
> I think that the making default codec is another issue. 
>  
> Thanks,
> Kang
> --------------------------------------------------------
> The numerous wireline legacy ITU-T G.7xx codecs and other 
> countless codecs deployed for mobile phones are a disgrace IMHO.
> 
> The industry would be better off adopting "Internet codecs":
> The iLBC RFC 3951 and RFC 3952 as the default codec and SPEEX 
> for variable rate wideband
> (ftp://ftp.rfc-editor.org/in-notes/internet-drafts/draft-ietf-
> avt-rtp-speex-
> 00.txt).
> 
> Thanks, Henry
> 
> 
> -----Original Message-----
> From: [e-mail] [mailto:[e-mail]]
> Sent: Tuesday, February 21, 2006 8:29 AM
> To: Kang Tae-Gyu
> Cc: [e-mail]
> Subject: Re: [Sipping] Use cases of multi-transcoding
> 
> 
> Hi Kang,
> 
> just a comment to the transcoding scenario between two 
> different WB codecs (WB1<->WB2).
> 
> Transcoding as such should be avoided because it is 
> inherently decreasing the audio/speech quality ("adds e.g., 
> delay impairments and Ie, equipment impairment factors") and 
> an "expensive" network function.
> There must be therefore an agreed justifaction, particularly 
> for WB1<->WB2 transcoding scenarios!
> 
> Transcoding between two different NB codecs (NB1<->NB2) is 
> often inevitable.
> 
> The difference with WB codecs is that terminals "should 
> support a fallback mode to a NB codec" in my opinion. There 
> are two possibilities:
>       NB mode is part of the WB codec modes of operation 
> (e.g., G.729EV
>       with G.729A as NB mode), or
>       separate NB codec (e.g., terminal concept according G.725).
> 
> The inconsistent "WB1<->WB2" E2E scenario might then lead to 
> fallbacks to
> (default) NB codecs. In case of a then "NB1<->NB2" 
> inconsistency to NB transcoding in the network.
> 
> Comments?
> 
> Albrecht
> 
> 
> 
> 
> 
> 
>                       "Kang Tae-Gyu"
> 
>                       <[e-mail].         To:      
> <[e-mail]>
> 
>                       kr>                      cc:      
> [e-mail],
> [e-mail], [e-mail],     
>                                                
> [e-mail]
> 
>                       21.02.2006 03:12         Subject: 
> [Sipping] Use cases
> of multi-transcoding                                  
>                       Please respond
> 
>                       to Kang Tae-Gyu
> 
> 
> 
> 
> 
> 
> 
> Hello,
> 
> I would like to discuss about the use case of 
> multi-transcoding. First of all, I am sorry for that I could 
> not answer about its use case when I received the question 
> from the floor, IETF 64 Vancouver meeting, because of poor 
> English. Also, thank you for the minutes(chairmen and note takers).
> 
> There are three kinds of use cases of multi-transcoding.
>  -    one or two more heterogeneous networks
>   -    one or two more ITSPs
>   -    one or two more wideband speech codecs
> 
> 
> 
> There are one or two more heterogeneous networks: enterprise 
> networks using IP-PBX, ITSP(Internet Telephony Service 
> Provider), IMS in 3GPP2, PacketCable, and Wibro. They will 
> not use a common codec. So, they need multi transcoding such as;
>  -    use case 1: A(a) - IP PBX T1(a-b) - ITSP T2(b-c, b-d) - 
> IMS T3(a-d,
> d-e) - D(d)
>  -    use case 2: A(a) - IP PBX T1(a-b) - ITSP T2(b-c, b-d) - 
> PacketCable
> T4(c-d) - F(d)
>  -    use case 3: E(e) - IMS T3(a-d, e-d) - ITSP T2(b-c, b-d) - Wibro
> T4(a-d, d-c) - G(c)
> 
> 
> 
> There are one or two more ITSPs or SBC because all of 
> internet telephony subscribers will not subscribe only one 
> ITSP. There are a lot of domestic ITSPs and international 
> ITSPs or ITXP. Internet telephony should be supported any 
> kind of terminal vendor even though it supports any specific 
> codec. It also supports multi call forwarding service. So, 
> they need multi transcoding such as;
>  -    use case 4: C(c) - ITSP T2(c-b, b-d) - ITSP T6(b-a, b-d) - ITSP7
> T7(a-d, d-e) - G(d)
> 
> 
> 
> There are one or two more wideband speech codecs. There has 
> been developing one or two more wideband speech codecs for 
> internet telephony: AMR-WB in 3GPP, VMR-WB in 3GPP2, G.729EV 
> in ITU-T SG 16 Question 10, a wideband codec in ITU-T SG 16 
> Question 9, and AAC in ISO/IEC. In this convention, Capital 
> letter means a node and lowercase(a, b, c, d, and e) means a codec.
> 
> A wideband codec encodes voice using 16,000 samples per 
> second (50 ~ 7,000Hz), as opposed to the 8,000 samples per 
> second (300 ~ 3,400Hz) by narrowband codec. A voice quality 
> of wideband codec is better than one of narrowband codec due 
> to support wider band. A tandem transcoding means to encode 
> narrowband codec such as G.711. So, it makes down sampling 
> and worse the voice quality. If two parties(calling party and 
> called party) have two different wideband codecs, transcoders 
> should transcode a wideband codec to another wideband codec 
> without tandem transcoding. If we use a common codec with 
> G.711(tandem), there is no more need multi-transcoding. But, 
> we need a multi-transcoding for supplying a wideband speech 
> high quality to each sides.
>  -    use case 5: wideband codec to wideband codec without tandem
> transcoding
> 
> 
> 
> Multi transcoding signaling can be useful for internet 
> telephony environments supported by standard; an example VoIP 
> network in quality of service for next generation Voice over 
> IP networks, MSF-TR-QoS-001.final,
> 2003 Feb, and Telecommunications and Internet Protocol 
> Harmonization over Networks (TIPHON) Release 3; End-to-End 
> Quality of Service in TIPHON Systems; Part 3: Signalling and 
> Control of End-to-End Quality of Service (QoS)-V2.1.2, 2002.
> 
> Multi trascoder can cover the use case using one or two more 
> conference bridge transcoding model.
> 
> We would like to discuss open these use cases or another use 
> case. Comments are welcome.
> 
> Thanks,
> Kang
> 
> 
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> 
> 
> 
> 
> 
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> 
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> 
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